The first type of chatter is generally harmonic resonance in the tip and tail induced by vibration from speed. It is more pronounced on soft boards with rockered tips and especially noticeable with full rocker. This type of chatter is more prevalent at low edge angles but can occurr in a carve as well. If this flutter occurrs during a critical phase of the carve, such as in the bottom of the heelside carve, it can induce an uncontrolled skid and total loss of edge hold.
The second type of chatter is a result of either imperfect riding technique at a critical phase of a high performance carve under demanding conditions, or simply going beyond the performance capabilities of the equipment in given conditions. In this case, ultimately both tip and tail will chatter as edge hold at the contact points fail but the incipient skid almost always begins at the tail due to the excessive forces generated in the bottom of turn.
Because total edge failure usually occurrs immediately following this incipient tail skid, it feels simultaneous and is often difficult for the rider to regain control. The only options available to the rider is to flex as low as possible to absorb the chatter, shift the board out ahead in an aggressive aft shift of the riders weight and try to decrease the rate of turn.
Obviously, prevention is the best strategy. Perfecting technique through the full use of flexion-extension, fore-aft movements and reducing over rotation and proper timing is crucial to reducing this incipient skid to prevent edge failure.
Many thanks for the detailed explanation. I have ridden a soft rockered board but have not experienced the first type of chatter you mentioned. Maybe I did not get it up to the critical speed for the resonance to play up.
For the second type of chatter, I used to get it more than currently with the exact same set of equipment. Maybe I am getting better in bending my knees more. Next time I will see if the aft shift will further eliminate this chatter for me. Thanks again.
But after reading your explanation, I begin to think the second type of chatter may have an element of the first type of chatter (resonance) in it. Does it not?